For edutainment, here's Greenland superimposed over the US eastern seaboard after adjusting for Mercator projection distortion.
https://www.thetruesize.com/#?borders=1~!MTQ5ODUwMjI.OTMwODU...
Clicking the outline will let you drag it around, and when it's selected the compass-rose in the corner can be twisted to change the orientation.
For the right price, America could probably it. There are only 56,000 Greenlanders, meaning that you could give each a million dollars at $56b, only about 1% of the federal budget. Do Greenlanders feel that attached to Denmark that they would refuse a million bucks?
> For purposes of National Security and Freedom throughout the World, the United States of America feels that the ownership and control of Greenland is an absolute necessity.
I'm not seeing any mention of "buying" here. Given his comments on the Panama canal, I think you should assume he has other options in mind for acquiring Greenland.